JSC2005-E-08203 (25 February 2005) --- Astronaut Piers J. Sellers, STS-121 mission specialist, wearing a training version of the Extravehicular Mobility Unit (EMU) space suit, participates in an extravehicular activity (EVA) simulation while anchored on the end of the training version of the space shuttle Remote Manipulator System (RMS) robotic arm in the Space Vehicle Mockup Facility at Johnson Space Center. The RMS has a 50-foot boom, called the Orbiter Boom Sensor System (OBSS), extension attached which would be used to reach underneath the orbiter to access tiles. Lora Bailey (right), Manager, JSC Engineering Tile Repair, assisted Sellers. Astronaut Michael E. Fossum (center), mission specialist, also participated in the test of the OBSS.